Which of the following is correct about lectin receptors?
- A. They recognize microbial carbohydrates
- B. They are expressed on phagocytes
- C. They can be classified as pattern recognition receptors
- D. All of the above is correct
Correct Answer: D
Rationale: The correct answer is D - All of the above. Lectin receptors recognize microbial carbohydrates, are expressed on phagocytes, and can be classified as pattern recognition receptors. Lectins are proteins that bind specifically to certain carbohydrates, allowing them to recognize and interact with pathogens. Phagocytes express lectin receptors to help identify and engulf pathogens. Additionally, lectin receptors are considered pattern recognition receptors because they recognize specific patterns or structures commonly found on pathogens. Therefore, all three statements are true, making option D the correct answer.
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A patient with systemic lupus erythematosus (SLE) is admitted to the hospital for evaluation and management of acute joint inflammation. Which information obtained in the admission laboratory testing concerns you most?
- A. The blood urea nitrogen (BUN) level is elevated.
- B. The C-reactive protein (CRP) level is increased.
- C. The anti-nuclear antibody (ANA) test is positive.
- D. The lupus erythematosus (LE) cell prep is positive.
Correct Answer: A
Rationale: An elevated BUN level may indicate kidney involvement which is a serious complication of SLE. The other findings are expected in SLE and do not indicate an urgent problem. CRP is a marker of inflammation and positive ANA and LE cell prep are diagnostic of SLE but do not indicate acute complications.
A patient’s documentation indicates he has a stage III pressure ulcer on his right hip. What should the nurse expect to find on assessment of the patient’s right hip?
- A. Exposed bone, tendon, or muscle
- B. An abrasion, blister, or shallow crater
- C. Deep crater through subcutaneous tissue to fascia
- D. Persistent redness (or bluish color in darker skin tones)
Correct Answer: C
Rationale: Stage III pressure ulcers penetrate through all layers of the skin but do not expose underlying structures such as bone or muscle.
What outcome would you least expect if the amount of template in a PCR fell significantly below the optimal amount?
- A. non-specific amplification
- B. increased yield
- C. Allelic drop-out (some alleles fail to amplify)
- D. Longer targets amplify poorly or fail
Correct Answer: B
Rationale: The correct answer is B: increased yield. If the amount of template in a PCR falls significantly below the optimal amount, it would be expected to result in a decreased yield rather than an increased yield. The template is essential for DNA amplification in PCR, and a lower amount would lead to fewer copies being produced. Non-specific amplification (choice A) can occur if there is too much template or incorrect primer annealing. Allelic drop-out (choice C) is likely to happen if there is insufficient template present to amplify all alleles. Longer targets amplifying poorly or failing (choice D) is also a common outcome when template concentration is low. Therefore, the least expected outcome would be an increased yield as that goes against the principle of PCR amplification.
What is the process called when a specific lymphocyte binds its antigen and proliferates?
- A. Clonal deletion
- B. Clonal selection
- C. Antigen presentation
- D. Cytokine signaling
Correct Answer: B
Rationale: The correct answer is B: Clonal selection. During clonal selection, a specific lymphocyte recognizes its specific antigen, binds to it, and undergoes proliferation to generate a large population of identical cells to combat the antigen efficiently. This process ensures an effective immune response.
Incorrect choices:
A: Clonal deletion - This process involves the elimination of self-reactive lymphocytes to prevent autoimmunity, not the proliferation of antigen-specific lymphocytes.
C: Antigen presentation - This is the process by which antigens are displayed to immune cells for recognition, not the proliferation of lymphocytes.
D: Cytokine signaling - While cytokines play a role in immune responses, they are not directly involved in the proliferation of lymphocytes in response to specific antigens.
One of the most significant factors in determining when to start antiretroviral therapy in a patient with HIV infection is:
- A. Whether the patient has high levels of HIV antibodies
- B. Confirmation that the patient has contracted HIV infection
- C. The patient’s readiness to commit to a complex, lifelong, uncomfortable drug regimen
- D. Whether the patient has a support system to help manage the costs and side effects of the drugs
Correct Answer: C
Rationale: Patient adherence is critical for successful antiretroviral therapy. Ensuring the patient is prepared to follow the regimen long-term improves outcomes.